As dusk fell over Philadelphia City Hall on Tuesday evening, Yancy Harrell painfully recalled the murder of his youngest son, Charles.

Speaking during a vigil held to honor the victims of last week’s shooting at Marjory Stoneman Douglas High School, Harrell detailed the night in 2011 when his son was killed. While Charles was sitting in a car waiting to pick up his sister, two young men who had mistaken him for someone else shot him four times.

He died hours later from his injuries at age 18.

“I will never have an opportunity to see him get married, graduate from college,” Harrell said, adding that Charles was killed less than a month before he would become a father himself.

“My grandson will never know his father,” Harrell shouted, seemingly loud enough for the entire city to hear. “He will never have an opportunity to play ball with his dad, or for my son to teach him how to ride a bike.”

Tragedies like the one that took Charles’ life, and the event that took the lives of 17 people in Parkland, Florida, on Feb. 14, persist because we have all failed to take action, Harrell said.

“We have failed our children!” he cried, his voice cracking with emotion, his words echoing through the streets.

In their son’s memory, Harrell and his wife, Victim Services Supervisor for the City of Philadelphia Movita Johnson-Harrell, co-founded the Charles Foundation, a non-profit that works to end gun violence. Both of Charles’ parents spoke at Tuesday’s vigil.

“We are here because we want to say, ‘No more,’” Johnson-Harrell said. “We all must work together to protect our communities, to protect our children, and to protect our nation.”

Speakers at the vigil articulated their message with three words: “demand the ban,” calling legislators to make semi-automatic assault weapons, like the one used in the Parkland shooting, illegal nationwide. Philadelphia District Attorney Krasner challenged the media to contact district attorneys across Pennsylvania and ask them where they stand on the issue.

“You put them on the record,” Krasner said. “You make them own what they have to say about this.”

Krasner said that “far too many of them are in the pocket” of the National Rifle Association (NRA), just like many of the members of Congress, “as has been the tradition in American politics for a very long time."

The district attorney emphasized that the time has come for elected officials and the NRA to be held accountable.

“We are here to stand for what is right. To protect our children, to protect our residents from gun violence,” Krasner said. “If we have to go straight after the NRA, and we have to go straight after people who believe cars should be regulated but guns should not, then we’re going to do it.”

Bryan Miller, executive director of the faith-based Heeding God’s Call, lost his only brother, an FBI agent, to gun violence. Miller said his brother was killed alongside two other law enforcement officers in 1994 inside the police headquarters in Washington, D.C. by a man with an assault pistol.

“We allow people in this country to acquire sufficient firepower to overpower law enforcement officers everywhere,” Miller told the crowd.

In the spirit of taking action, Miller’s organization, along with the Charles Foundation and several other anti-violence groups, have organized a protest on the morning of Wednesday, March 21, to “demand the ban.”

At the event, activists will gather at the Arch Street Friends Meeting House to ceremonially melt down an assault weapon and repurpose it into a garden tool. Then, they will proceed to Senator Pat Toomey’s Office on Chestnut Street to demand Toomey co-sponsor an assault weapons ban in Congress.